A variety of substantially water insoluble particulates are known and useful in treating fabrics. For example, fluorescent whitening agents, also known as optical brighteners, or brighteners, which are adsorbed onto textile fibers and impart to the fabric an improved degree of whiteness or brightness (fluorescence) by means of their chemical ability to absorb ultraviolet radiation and re-emit visible radiation, have found widespread use as components of household detergent compositions. In order to provide substantial fabric whitening, it is desirable to combine the optical brightening capacity of fluorescent whitening agents with an effective bleach. Fluorescent whitening agents are, however, very reactive and generally unstable in liquid chlorine bleaches. The prior art has failed to provide a stable product incorporating fluorescent whitening agents in a liquid chlorine bleach.
U.S. Pat. No. 3,393,153 to Zimmerer et al. discloses the use of an oxidized polyethylene emulsion as a stabilizing agent for dispersions of fluorescent whitening agents in bleach. These emulsions, however, have been shown to substantially lack both physical and chemical stability.
Problems of physical and chemical stability are compounded when particulate pigments, or bluing agents, such as ultramarine blue, are also incorporated into the bleach composition. Bluing agents deposit on a fabric surface and, in contrast to optical brighteners, reflect blue light while absorbing yellow light. Although addition of bluing agents in conjunction with laundering additives is a desirable means of treating fabrics, it has been difficult to sufficiently stably suspend the bluing agents, particularly in a strongly oxidizing environment such as hypochlorite bleach, while retaining water dispersibility of the solution.
U.S. Pat. No. 4,271,030, issued June 2, 1981, inventors Brierley et al., discloses a liquid hypochlorite bleach having a particulate pigment, such as ultramarine blue, which is said to be stably suspended in the composition by means of a flocculant, such as calcium soap flocs and amine oxides, filling at least 50% of the volume of the composition; and, U.S. Pat. No. 3,663,442, issued May 16, 1972, inventor Briggs, discloses liquid bleaching compositions having a finely particulate terpolymer which imparts opacity to the compositions.
However, prior known compositions with particulates in aqueous solutions have posed sedimentation, coagulation or stability problems or have not found commercial acceptability as dual bleaching and bluing compositions. Co-pending application Ser. No. 574,565, filed Jan. 27, 1984, is addressed to stabilizing bluing agents in chlorine bleach compositions; this application, as noted above, relates to stabilizing both optical brighteners and bluing agents in chlorine bleach compositions.